T-lymphocytes are divided into two main sub-classes: CD4+ and CD8+. Which of the following statement(s) is/are true concerning these classes of T-cells?

a. CD4+ T-cells are restricted to recognizing antigens of the class II major histocompatibility complex (MHC)

b. CD8+ T-cells perform primarily cytotoxic functions 

d. CD4+ T-cells also perform suppressor functions

T-cells are divided into two main sub-classes: CD4+ and CD8+. CD4+ 8+ double positive cells are usually immature Tcells or thymocytes while the fully differentiated T-cell is usually single positive. Because of molecular interactions, CD4+ T-cells are restricted to recognizing antigens in the context of class II major histocompatibility complex (MHC) and usually perform roles related to B-cell help, T-cell help, and inflammatory responses such as delayed and contact hypersensitivity. CD8+ T-cells are restricted to class I MHC and perform cytotoxic functions. In addition, experimental studies have demonstrated that both CD4+ and CD8+ T-cells can act as T suppressor cells.